For attaching an integrated circuit on a chip in such a way that it is in electrical contact with a circuitry pattern, methods are known for direct attachment of the chip by flip-chip technology, or the chip can be attached in such a way that a separate structural part, onto whose surface the chip is attached, is connected to the smart label.
Methods based on flip-chip technology have for example the following disadvantages:
the production line is complicated, expensive and inconvenient in view of further development, because all the operations are integrated on the same line, and
the placement of the chip on the smart label requires that the tool used has a long path and also that the chip is positioned very precisely in the correct location.
The smart label can also be provided with a separate structural part comprising an integrated circuit on a chip, attached on a film material. The electrical contact between the integrated circuit on the chip and the circuitry pattern of the smart label is formed so that the film material of the separate structural part comprises a conductive layer which is connected to the chip and which layer is brought into contact with the circuitry pattern in connection with the manufacture of the smart label by connecting both ends of the strip-like structural part to the circuitry pattern, that is, the structural part is off the smart label in the area between its ends. The structural part is attached to that side of the smart label on whose opposite side the circuitry pattern is located so that the chip comes against the smart label.
The above-mentioned methods involve for example the following problems:
In some existing smart labels, the distance between the structural part and the circuitry pattern and simultaneously the distance between the integrated circuit on the chip and the circuitry pattern are changed by bending, because the structural part is not wholly attached to the smart label, wherein the stray capacitance affecting the frequency of the electrical oscillating circuit is changed, and
the smart label has a relatively thick construction, which is disadvantageous in further processing steps.